Safety apparatus of a door closer



June 7, 1938. M. HASUO SAFETY APPARATUS OF A DOOR CLOSER Filed June 3, 1936 M- Hallo.

Patented June 7, 1938 UNITED STATES PATENT OFFICE assignor to Nippon Kanagn aha, Osaka, Japan Application This invention relates to door checks of the kind which employ the pressure of a fluid to control the movement of the door.

According to the present invention there is provided a door closer of the kind referred to comprising a cylinder and a tubular piston movable therein, the said piston at one end thereof aifording a seating for a check valve casing, which is adapted to be held in positionv by means of. a

a spring operable also as a door closing force and is shaped to provide a seat for a check valve, closing of the door causing the piston to be moved in such a manner that the check valve is pressed against its seating, the check valve casing being lifted bodily from its seating against the action of the spring, if fluid pressure rises to too great an extent.

It may be mentioned that it has previously been proposed to provide checking appliances of various descriptions fitted with a spring supported relief valve whereby the risk of damage due to the door being forcibly closed against the checking resistance is obviated. For example, it has been proposed to provide a door check having a tubular 3 piston rod provided with a relief valve controlled by a spring and having an external regulating device, so that under normal working conditions the power of the spring is sufficient to resist the pressure of fluid in the checking chamber of the cylinder except that it allows the usual leak off of the fluid to take place; (such as by forcibly closing the door) but when the pressure is raised beyond the normal, the spring yields and allows the fluid to pass more rapidly through the piston from the checking chamber and escape into the cylinder behind the piston through a suitable relief port in the piston rod.

The object of the present invention is to provide a simple door check mechanism of improved con- 0 struction adapted to prevent damage that might be caused by forced closing of the door at a speed higher than the rated closing speed of the door check.

In order that the invention may be clearly un ,5- derstood and readily carried into efiect, reference is made to the accompanying drawing, which shows diagrammatically and by way of example a door check in accordance with the present invention.

0 The door check is provided with a check valvg casing I, which is independent of a piston 2, an is tightly pressed against an oil passage 3 provided in a head plate 4 of the piston 2 by the force of a helical spring 5, in order that the oil passage is 3 may always remain closed at the inside of the Kabushiki Kwai- June 3, 1938, Serial No. 83,340 In Japan June 14, 1935 piston 2, except in an emergency when the check valve casing I itself acts as a safety valve and protects'the door check from damage, in a manner to be described hereinafter. i

If a door fitted with a door check which lacks 5 any safety device, happens tobe closedeither by hand or by other means at a higher speed than the door check permits, the pressure of the damping liquid such as oil, which acts on the piston, rises suddenly, often beyond the pressure 10.

that the construction will stand, with the result that parts of the door check may be damaged or the wooden door may yield to the'press'ure and break.

As the drawing shows, the .main component parts of the door check are a casing 5, the piston 2, the check valve casing l, and the helical compression spring 5. The casing 6 is of cylindrical shape and is filled with liquid such as; oil I. A pinion 8 which is rigid with a shaft 9 meshes with a rack I0 provided on the piston '2. When the door is opened, the shaft 9 and the pinion 8 are rotated in a clockwise direction, driving the piston 2 to the left and compressing the-helical spring 5, and at the same time a ball check valve IS in the check valve casing opens an oil passage II and allows the oil to fill the space in an oil chamber I. When the door is closed, the compressed helical spring 5 drives the piston 2 to the right and the pinion 8 and the shaft 9 then rotates in a counter clockwise direction, the check ball valve [3, in this case, closingithe oil passage II and the oil in the oil chamber ll escapes only through a narrow oil passage I82 If the door be closed by force at too great a I speed, the pressure of the liquid existing in the oil chamber l4 increases, owing to the rapid and hard drive of the piston 2 to the right, to such an extent that it finally overcomes the setting force of the spring 5 and moves the check valve casing l bodily from the head'plate 4 of the piston 2, leaving the wide oil passage 3 openv for the abnormally compressed oil to'pass freely out of the oil chamber l4 into 'theinterior of the piston 2 and the normal state of the oil in the oil chamber I4 is instantly restored. As the result of the check valve casing I thus automatically acting as a safety valve,the door check device as a whole is safeguarded and there is substantially no possibility of damage even if the door be closed too fast.

The adjustment of the closing speed of the door may be very simply and easily effected by a regulating screw rod II. If the rod I! be turned to the right a port I6 in connecting the oil passages ll becomes restricted and consequently a therein, the said piston at one end thereof aifording a seating for a check valve casing, which is adapted to be held in position by means of a spring operable also as a door clomng force and is shaped to provide a seat for a check valve,

closing of the door causing the piston to be moved in such a mannerthat the check valve is pressed against its seating, the check valve casing being lifted bodily from its seating against the action of the spring, if the fluid pressure rises to too reat an extent.

2. A door check of the kind referred to comprising a cylinder and a tubular piston movable therein and having apart thereof in the form of a rack adapted to mesh with a driving pinion in such a manner that closing and opening of the door causes the piston to be moved longitudinally within the cylinder, a check valve casing housing a check valve being disposed adjacent to and within one end of the piston in such a manner that the check valve casing affords a safety valve during closing of the door in order to prevent the fluid pressure rising too high.

3. A door check according to claim 1, wherein the spring is of helical. form and is disposed between the check valve casing and the oppsite end 1 of the cylinder in order to maintain the check valve casing on its seat and to provide a door closing force.

MASAICHI HASUO. 

